Hope this helps, as far as i know most subaru models had around 50mm offset. Most aftermarket wheels range from 45-55mm depending on the make. So the offset is fairly much the same as vauxhall, however most calibras were only 4X100 stud pattern (except v6 and turbo 5x110) whereas the subarus use 5x100. So i'm afraid theres no way of fixing them on.